Silver Source Thirteen
by Ardil the Traveller
Summary: The engineers of Silver Source Thirteen, one of the highly refined Moon Stones that keeps Soltis aloft, are faced with an unprecedented blackout immediately followed by an attack on the vast city - but their true foe is one they could never have expected. The race to repair and safeguard their Source while maintaining the Dome of Light may give them one last chance as Soltis falls.
1. Blackout

This was originally intended to be part of the "Six Shades of Ruin" project (which I haven't forgotten and will be updating!), but it got a lot longer and seemed set on being its own story. Hope you enjoy! Concrit, as ever, is greatly appreciated!

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"...so then I heard-" Castiel's voice cut off as the building thrum that had underlain his words peaked, and the lights of the hall faded into pitch blackness. Voices cut through it, seeming to come from every direction as they echoed one another in confusion and fear.

"Ow!" "What happened?!" "What's going on?!" "I can't see!" "Moon's Light!" "Where are you?!"

"Silence!" a woman shouted into the growing panic, enough authority in her voice that the majority obeyed the order. Castiel listened to the hush, his unease growing. Something was very, very wrong. He only realised what he'd missed as it began again: the faint, undying background vibration, more felt than heard, that spoke of the life of the city. For that brief time, Soltis' halls had rung with confusion, but the city itself had fallen utterly silent. Blue-white light traced circuitry patterns along walls, floors, and ceilings, and the soft illumination of the city's internal day sprang back to life. The cool light revealed the turmoil wrought by the seconds of darkness, ordinarily calm people frozen mid-stride, or fallen to the floor, or clutching at the walls – or even one another.

Glancing at his companion, an engineer a couple of ranks higher than Castiel himself, he asked

"What do you think _that_ was all about?"

Meredin shrugged. "It can't have been our doing, but we should get back to the Core and find out just what _did_ cause it."

The Core was the local engineers' nickname for the immense Silver Moon Stone that had been a part of the continent since time immemorial, painstakingly excavated from rock and earth and purified in situ through tremendous effort. Much smaller than its former self, it held if anything more power than it had before, resisting the pull of Arcadia's gravity and powering a section of the city with energy to spare.

"You're right! There weren't any kind of tests scheduled for today, were there?"

A headshake. "Not that I know of, and nothing we've done has ever caused something like this. I can't think of anything that could have. Better get down there before something worse happens and we both get demoted back to Tenth."

"_Ouch_," Castiel said, with feeling. He was a fourth-rank local engineer, and Meredin a second, just one rank below the First Engineer who oversaw all work to do with their particular Core. They'd both earned their positions by their own merit and nothing more, like all Silvites, at least in theory. But a catastrophic failure would see them damned for their own incompetence unless there was no way they could have prevented the disaster.

"You!" a voice rang out as they turned back the way they'd come, close by and definitely female. Startled, Castiel stopped dead, looking back over his shoulder to see a woman closing on them rapidly. She was wearing a long-sleeved white dress that left her shoulders bare and split a little below her hips. Decorated in places with a silver circuitry pattern, together with a silver headband, the style of her clothing and tone of her voice told the two engineers that she was someone technically more important than either of them, although not directly related to their line of work.

"You're engineers, aren't you?"

"Er... that's right, ma'am." Like hers, Castiel's and Meredin's clothes gave away their position in life quite well. There was a lot more light grey in their somewhat simpler outfits, its thin, soft weave belying its prowess as an exceptionally damage-resistant and insulating fabric. The exact detailing and patterning of the clothing denoted their precise status, for anyone who was interested enough to care.

"Do you know what just happened?"

She wasn't demanding they tell her, although he suspected a part of her wanted to, and that, at least, was good. A lot of people expected all engineers to be able to solve anything, instantly, and while they were good, they weren't that good.

"No, ma'am. We were about to start back to the Core – that's what we call the Stone here, Silver Source Thirteen – to find out."

"Good." She scrutinised them for a moment. "Fourth and Second rank Engineers? End of your morning shift?"

Startled, Castiel nodded. "That's right, ma'am."

"You'll take me there with you."

Castiel blinked at the abrupt statement. "What, to the – to Silver Source Thirteen, ma'am?"

"Yes, unless it isn't permitted for me to view the Source."

"No, there's no rule against it, but..." He let himself trail off. Dissuading her would be more trouble than it was worth with whatever had just happened still hanging over their heads, and as long as she'd stay out of the way – which he'd expect her to be able to; few people rose high without a level head on their shoulders – then she wouldn't be much of a problem.

"Good. Lead on, then."

The two engineers started walking again, sharing a quick glance that spoke more than any words they might have exchanged.

"Now that's sorted out," she said, falling into place behind them, "we should introduce ourselves. I'm Celesia."

Castiel and Meredin responded with their names automatically before something registered in Castiel's mind, prompting him to speak and cut her off.

"Ple-"

"Celesia – not Sector Prime Celesia?!"

"Er... yes, actually."

He looked over his shoulder to see her looking slightly uncomfortable at his outburst, and turned around, now walking backwards with practised ease, to look at her again. Celesia's hair was dark for a Silvite, but still recognisably blonde rather than the foreign light brown, and her eyes were a brilliant green that Castiel had known his sister envy. Soltis was divided into six sectors both physically and politically; seven if the Elders' Spire was considered as well. The Sector Primes governed the six sectors, and in turn answered to the Elders, who also oversaw the Primes of other cities. Soltis was simply the largest Silvite city, and the capital.

Celesia covered a smile with a slender hand, but Castiel could still see it dancing in her eyes. This close to, he wondered how old she was. Silvites lived a long time, the average lifespan of a Soltisian noticeably longer than any of their less advanced cousins beneath the other Moons, but she didn't look all that old.

"You should be more careful, Engineer Castiel. You can't see where you're going."

Despite himself, he found himself wanting to smile back at her light tone. "I know my way around well enough, Sector Prime. If we have to make repairs in the dark, I'm well prepared."

She chuckled, and beside him, Meredin laughed.

"Hey, don't youuu-!" The entire city trembled, a crash as much felt as heard rolling through it, and Castiel fell backwards to the floor. Marginally more stable, Meredin managed to keep his balance, and Celesia clung to the hall's central divider for support.

"That was an impact on the Dome of Light!" she exclaimed, shocked. Propping himself up on his elbows, Castiel stared up at her, disbelieving.

"An... an attack?"

Another impact sent its shockwave rippling faintly through the city, and his eyes widened further as Meredin shouted "Sabotage!"

At once, everything fell into place. The unprecedented power fluctuation – somehow, something or someone had infiltrated the city of Soltis, and their army was attacking from the outside even as unknown agents within attempted to disable the power sources for the Dome of Light!

"They must have meant to disable our power and attack when we couldn't defend ourselves!" Celesia shouted, echoing Castiel's own thoughts. "But they didn't count on the strength of our defences – or our engineers! They won't underestimate us again!" She extended a hand to Castiel, who took it automatically, letting her help him up. "Second Engineer Meredin, head back to the Source, to your Core! They'll need you! Fourth Engineer Castiel, stay with me!"

Neither of them thought to argue, Meredin nodding and dashing off, keeping his footing even as a third tremor shook the city.

"What are they doing?!" Castiel exclaimed. He'd experienced several such attacks, and often all that could be made out from inside was a dull booming in the outermost two or three levels of the city. Only when the Gigas Bluheim and Plergoth had been brought to bear on their defences had anything like this happened, and so far they were the only ones to have attacked them directly. Bluheim had retreated unharmed after carrying out a lightning-fast strike that had shaken the populace but caused little damage, but Plergoth only when the Gigas itself had been wounded by a cleverly programmed drone.

"I don't know... a Gigas?" She started moving as she spoke, running on down the hall. The orderly flow of Silvite life had been utterly disrupted, and people were trying to go in all directions on both sides of the hall, with the result that they were creating tangled knots of confusion everywhere. Castiel followed her, pushing people aside where he had to, fighting to keep the determined Sector Prime in sight and within reach. "The Blue Gigas' appearance two months ago was designed to test our defences. It must have been. Perhaps this is their real attack!"

It was the best theory either of them could come up with. Celesia stopped at the first public terminal, Castiel almost carried past her by a sudden flow of people. Quickly providing the authorisations appropriate to her station, she convinced it to display an external view of the city, panning the camera up and around to angle it towards the Dome of Light and the invading fleet she expected. But only plumes of smoke marred the sky, as if several ships had fallen in battle, too few for a fleet yet leaving none behind, either fleeing or fighting.

"Look at the roof!" Castiel shouted, peering over her shoulder. Obediently, her gaze dropped to the bottom of the screen, and she gasped, panning down again. The broad and roughly level expanse of white that formed the roof of whichever section of the Sector she'd accessed was dotted with defence drones, floating automatons that policed and protected all Silvite cities. Normally, the larger units would be mobilised outside the shield to fight off attackers, but now robots of all sizes mingled, seeming to almost crouch against the city as if afraid.

"What are they hiding from?" he asked. Celesia had no response, beginning to aim the camera up again as the city rumbled once more, and Castiel grabbed her arms to stabilise both her and himself, only really becoming conscious of his action after the shaking had died. At once, he let go again.

"I'm sorry, Sector Prime!"

"It's all right." She shook her head. "They're dropping something on us, but I can't make out what. We've got to get onto the surface."

"To the surface?!" Castiel knew people who had never been above ground in their lives. Soltis provided everything they could possibly need. In the middle of an attack, he'd feel safer by far with its familiar ceiling above his head than he would protected solely by the immaterial Dome of Light.

"Yes, the surface! Traffic won't be permitted to fly, and after what just happened to the power I don't trust the teleportation system. I need to know what's going on out there, and the only way I can do that now is to get aboveground and see for myself!"

Reluctantly, he nodded.

"Now show me the nearest way up that doesn't involve the city's power!"

That, in Soltis, was a lot harder than it sounded. Almost everything relied on Silvite achievement one way or another, each generation building on the work of that before. Each one left a small addition to the vast legacy that was Soltis before their lives were over and they returned to the empty void of death. Knowing by the very nature of their innate magical gifts that there were no second chances, that life departed into the same void from which it so miraculously came, it was their philosophy to make every second worthwhile, and often to leave at least something that would live on after they themselves had returned to nothing. It had driven them on, further and faster than the other civilisations who wasted their one chance at life, or let their talents lie idle, expecting some other fate beyond death's blank and inescapable embrace. Castiel was forced to pause through several seconds, and two more impacts, before replying.

"...This way!"

He couldn't help but worry as he took off down the corridor. Was it his imagination, or were the attacks growing closer together? The Dome of Light could only protect them as long as it had power, and if there was another blackout, they'd be defenceless. Even without that, he knew that however magnificent it was, the defensive barrier had to have its limitations. It had never been tested to destruction even by the Gigas, and its theoretical strength was claimed to have been specifically calculated to withstand truly astronomical impacts, but even so, as an engineer he knew how disastrous it could be to assume anything was limitless.

Several more distant impacts sent ripples through the city before they even reached the stairs, and Castiel groaned as he realised they'd have to climb the entire twenty-three flights unaided.

"Are you sure about this? It's twenty-three floors to the top!"

"We don't have a choice, Engineer. I don't have a choice. If you want to, go back to Source Thirteen."

It was tempting. Very tempting. The Source would be providing a lot of power, and whatever had happened to it would have left it needing careful monitoring even if it were repaired. Though everyone would doubtless be there already, there would be a place for him, and he'd be welcomed unquestioningly. But however much he wanted to hide in familiarity, he knew he couldn't leave the determined Sector Prime entirely alone.

"I'll see this through, Sector Prime."

"Good. Then come on!"

She started taking the stairs two at a time, Castiel trailing behind, going faster than he felt comfortable with but still slower than she was. Only when a powerful shudder caused her to lose her footing and trip, sliding down several steps before she could catch herself, did she slow, and then only as much as she had to.

By the time they reached the top, both were out of breath. Celesia bent double, gasping, for several moments before forcing herself to straighten up and open the door to the outside world... revealing a scene neither had ever imagined even in their wildest fears.

Trails of smoke angled across the sky in unbelievable numbers. It wasn't Soltis that was under attack, but the entire continent – no, further than that. Nowhere could Castiel see an end to the streaks of darkness, growing thinner only with distance and continuing into the horizon until they became indistinguishable from one another and from the wounded sky.

"How are they doing this...?" he breathed, and beside him, Celesia clutched his arm in the first indication he'd seen that she might not be completely self-assured and in control.

"They're not..."

He looked at her white face, and followed its angle up until he, too, saw what she did and he returned her grip with one equally fierce.

"It's the Moon..."


	2. Falling Like Rain

Hi! I've decided to settle into a fortnightly update schedule, so if you're following this, check back in two weeks for the next chapter. Hope you're enjoying, let me know what you think - anonymous reviews as much appreciated as signed!

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Stunned and silent, the two Silvites stood side by side as the Moon Stones streaked across the sky, holding onto one another for reassurance and neither one really aware of it. The Silver Moon glowed between the trails, countless Moon Stones raining down from it, and more launching themselves into space with each minute that passed. Soltis trembled repeatedly as the Moon Stones hit the shield around it, actually bouncing off it, even in one case rolling down the dome's curve. The hexagons that made it up flared into brilliance with each new impact before fading back to their usual bluish translucency. All around, Soltis' artificial guardians crouched flat to the roof, as powerless to protect the city as its human occupants. Slowly, Castiel began to turn, his mind refusing to take in the panorama, the full scale of the destruction outside the Dome of Light. Hands locked tight on his arm, Celesia turned unresistingly with him, only to be stopped short.

"Light of the Moon, look!" His free hand shot up almost without his thinking about it, and she followed his gaze to gasp in shock. Half-hidden against the backdrop of smoke, an immense ship drifted downwards through the sky, trailing smoke, its striking inverted fin-shape already badly damaged. The long, tapering tail had been sheared off altogether, and the elegant fin had two vast holes punched through it. The triple-cloud shape of the ship's main body seemed almost the only thing left intact, and even as he watched, another Moon Stone only narrowly missed it.

"Seren..." Celesia's voice shook, and he couldn't work out what she was saying. A name? It wasn't his, and they were alone. "Seren, m-magnification device, please. Distance viewing."

Castiel looked at her, confused, and started as her hair suddenly slipped free of the elegant and intricate network of silver that had kept it chained tidily down her back. Letting go of his arm with her right hand, she gestured slightly into the air as instead of falling, the strands of silver flowed together into a sphere that floated to her hand before changing shape again. This time, what it became was twin adjustable-focus lenses secured firmly onto a strap. Celesia picked it out of the air and placed it on her head, letting it adjust itself once the position was roughly correct.

"Oh... oh no..."

"What do you see?"

"It's the _Ecliptic_... she's badly damaged, she's losing control. We can't get to her... we can't get help to her..."

The _Ecliptic_ was a masterpiece, one of the keystones of the Silver Civilisation's manned fleet. She had been constructed alongside the first Gigas of the other civilisations, and finished far faster. Yet, equipped with the highly adaptable Silvite technology, linked to life itself in ways no other civilisation could possibly comprehend, she had remained up to date, a valuable and famous component of their fleet.

"She's trying to self-repair, but she can't possibly navigate through all these Moon Stones. She's too large to have a hope of moving fast enough." Celesia bowed her head. "She'll be hit again before she can reach safety."

Castiel tightened his grip on her hand, and, grateful for the support, she responded in kind. They could do nothing but watch in horror as the magnificent ship was struck again, trailing smoke from the terrible damage; as its systems tried without success to conform to the ever-increasing demands of repair placed on them until, taxed beyond their limit, they could do no more. Still struggling valiantly towards the great continent on which Soltis rested, the _Ecliptic_ sank below their line of sight until nothing more could be seen of the once proud ship.

"Seren," Celesia said softly, tear tracks running unnoticed down her cheeks, "telescreen, please."

Once again, the pseudo-lifeform apparently known as Seren obliged, uncoiling itself from her head and forming its body into a floating screen that hovered before her. Under any other circumstances Castiel would have admired it, but he could barely feel more than a dull surprise. If anyone short of the Elders themselves were to be expected to own such a complex and well-programmed liqueform, it would have to be the Sector Prime.

"Connect me to my office."

There was a long pause, the screen blank in the air in front of them, before Seren finally produced a surprisingly organic-sounding chirp and it came to life.

"Sector Prime, you're unharmed! Where are you?" The voice was reproduced well enough that Castiel didn't think twice about it, vaguely recognising it and the image on the screen as the next in line for Celesia's own position. "We were afraid you had been injured!"

"No, I'm all right." Amazingly, she kept her voice calm and under control. "I had an engineer from Silver Source Thirteen escort me to the surface in order to ascertain what was happening. There was a power cut in my region and I couldn't trust the teleportation network. The impacts are Moon Stones, all Moon Stones. There is no enemy fire – there is no enemy. The Dome of Light is protecting us: the shudders we feel are remnant shock waves being transmitted through the shield and the rest of the continent. Have a broadcast prepared at once to explain this. We are Silvites, and we will bring ourselves through this storm unscathed."

"A-at once, Sector Prime." His voice faltered noticeably more than hers, and there was a hesitation before he spoke again. "What of yourself?"

"I feel it's my duty to stay here, to watch over the sector in person. Seren can continue to provide a link between us. Contact the other Sectors if you can and tell them what's happening, if they don't already know. We will survive this."

He nodded, resolve buoyed by her own. "Of course, Sector Prime." At the barest twitch of his wrist, on the very edge of the screen, the communication ended. Registering what she'd said a few moments late, Castiel looked at her.

"You're going to stay-" and his voice cut off for a moment as another impact jolted the city beneath their feet "-stay here? Outside?"

"Yes," she responded, still managing to keep her voice calm. "I need to be here – I need to see what's happening for myself."

"Why?" With nothing but the Dome of Light to protect him, able to see the suddenly inimical Moon above and the trails of destruction cloaking the sky, Castiel felt horribly exposed, wanting nothing more than to run and hide as deep in Soltis as he could.

"I can't risk using the teleportation system right now. The last thing this Sector needs is to lose its Prime in the middle of a catastrophe. Nowhere in Soltis is any safer from one of those Moon Stones... it doesn't matter where I am if it isn't my office." Unbidden, her hand reflexively tightened a little. "I can't be seen to run from this. And... I need to see it. To understand what we're facing."

"All right." Castiel wasn't sure he understood, but she had told him her reasons. He flinched slightly as yet another impact resounded against the shield, and Celesia tightened her grip once again.

"You can go back to the Source, Engineer. They may need you."

Without even really knowing why, Castiel shook his head. Part of him wanted to, to bury his knowledge of what was happening in work on the Source, but another part overruled it. He would stand atop Soltis beside the Sector Prime and face his fears, though there was nothing he could do.

"I'm staying here."

She looked at him again and gave a faint smile. There was nothing more to say, but for now, neither of them was alone. Side by side, the two Silvites looked out across Soltis, watching the fall of the Moon Stones against which even their own mighty civilisation was all but powerless. The automatons huddled around them only accentuated their helplessness, all staying low to the roof almost as if they, too, were cowering in fear. The only mobile things still standing on the surface were Celesia and Castiel.

Time passed in silence. The liqueform, Seren, settled itself back into Celesia's hair, chaining it neatly back again, though the air above Soltis barely stirred with the Dome of Light blocking out the wind. The already dark sky darkened still further, the trails of the Moon Stones crossing it so thickly that the blue was completely obscured, and still they fell, no pause or even slowing of their endless rain. One long hour became more, Celesia answering any number of communications, keeping her voice calm to make announcements, even speaking to the people of her Sector in reassurance, appearing calm in the face of what had begun to feel like the end of the world. Still, incredibly, Soltis' shield held. As the sky turned from smoky grey to black with what Castiel's timepiece told him had to be the natural sunset, he found himself speaking his thoughts, barely aware that he was talking at all.

"Do you think this will ever end?"

Looking up at the blackened sky, even the Silver Moon itself no longer visible, Celesia sighed before giving her slow answer.

"I don't know."

She sat down in the deepening dark, and Castiel sat beside her.

"It can't go on forever," she continued softly, trying to convince herself more than him. "It can't."

But as they watched the flaring of the shield, listened to and felt each new impact, it was feeling more and more as though this incomprehensible hell would continue until the end of time.


	3. Power Drain

Glad you're still enjoying! I have no intention of drifting quietly away, so without further ado, here, as promised, is the third chapter!

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Night came and went, Soltis' inhabitants resting uneasily, even Celesia and Castiel eventually drifting into uneasy slumber against the quiescent automatons. When morning came, it was with only a marginal increase in the dirty light, and only Seren's insistent chirps woke them.

"Nnnh...?" Castiel cracked his eyes open, automatically responding to the sound. "I'm awake... what time is it?" But no-one answered, not even with an increase in the illumination, and that in itself drew his eyes to open further. Only then did he realise where he was, what had happened. He was stiff from sleeping against hard surfaces, the rumbling of the Moon Stones a constant background to his uneasy slumber. It had crept into his subconscious and woven dark dreams he could no longer remember from the ephemera of his sleep. But whatever he'd dreamt, it was no worse than the world he'd opened his eyes to, for the Moon Stones still, impossibly, fell.

"Engineer Castiel?" asked a sleep-blurred voice from beside him. Celesia's eyes were faintly shadowed by her uneasy night. "It isn't over..."

"No," he confirmed, softly. Moons knew he'd hoped that it would have been over when he opened his eyes, even that it would never have happened at all. There was no hope left now that it could have been a nightmare. "Do you think it will end?"

"It has to." She bowed her head. "Not even the Dome of Light can protect us forever. If it doesn't stop, and we do nothing, every last Source will be bled dry, and the Dome will fall."

A chill gripped Castiel's heart at those words. The fall of the Dome of Light would see the first impact to truly fall on Soltis. It wouldn't destroy everything, not at first. Nor would the second impact, or even the third. But if the rain of Moon Stones continued endlessly, then eventually the entire splendid city would be reduced to craters and rubble. The last bastion of his world would be gone.

"It has to stop," he whispered, and beside him, Celesia straightened, once more the capable Sector Prime.

"It will." She stood, turning slowly to survey the darkened sky, the threatening world pressing in against Soltis' fragile-seeming shield. "We are Silvites, and it is _not_ our time to return to the darkness. Our legacy _will_ continue beyond this day, but we must fight for it as never before." It was her speech-making voice, he realised belatedly, that calm, assured, determined tone he'd heard so often as she spoke to her Sector. Nothing in her face or stance did anything to undermine the power that voice conveyed, not even fractionally, and Castiel felt as though she'd suddenly stepped to the other side of the continent, the distance of Sector Prime enveloping her once again. The worry, even fear she'd just let slip was gone, and he wasn't sure why, but it almost hurt even as her words lent him confidence.

He got to his feet, a little more awkwardly than she had, absently brushing his clothes down. They didn't crease for long, didn't pick up any but the faintest of marks, and the motion served to shake out what few effects his unusual night's sleep had left on them.

"I can take you to Source Thirteen, ma'am." He found he wasn't sure how to address her, opting for at least some of the respect her sudden distance seemed to demand. "We can monitor the power flows from there. If there's anything that we can do, that's where it'll be."

She nodded. "Good idea, Engineer. Maybe they'll have found the cause of that power cut, too." Her expression softened, just a little, as she looked at him. "Thank you for accompanying me here."

He shook his head. "You were right. I needed to see what was happening to understand it. I'm still not sure I do." He wouldn't have been able to leave her alone, but that he didn't say. They had given one another strength through the course of yesterday's continuing nightmare, and for all her capability, he realised even the person who was Sector Prime had to sometimes need someone to lean on. No-one, not even a Silvite, could be perfect. Not even the Elders themselves could be perfectly self-contained. He'd never thought of it before; they'd always been more remote figures in the distance of the background of his world, never really individual people until now. Somehow it added to her strength rather than detracting from it. He would never have stayed on the surface alone... yet even though she shared the same flaws, the same fears, Celesia would have.

"I don't know if anyone can," she said softly. "But we must try. Now, lead me to the Source."

Castiel nodded and obeyed, turning back to the door that would lead them back into Soltis. Entering its white-walled security once again, he glanced back just in time to catch Celesia doing the same, both of them looking over their shoulders at the terrible, wounded sky for a moment before she shook her head and shut the door, and Castiel quickly turned away. The Source was nearer to the surface than where they'd met, but it was still some floors down, and he wasn't looking forward to descending the steps again with the continent still ominously rumbling under their feet. Still, there was no choice, for either of them. He carefully began the descent, Celesia following behind him. There would be something they could do at the Source. There had to be.

When the two Silvites eventually left the stairwell, they were greeted by a sight that neither had ever seen before. The vast halls of Soltis were deserted, not a single person to be seen, a few automatons the only visible movement as they went about their programmed tasks. The faint, almost inaudible hum of Soltis' mechanical almost-life was suddenly the only sound to be heard beside their eerily echoing footsteps. Unprompted, Castiel stopped dead, one hand out to the wall as if to steady himself. It was as though the city were already dead.

"Where is everyone?" he whispered, almost afraid to break the terrible silence, to hear his own voice echo as the only sound in the whole of Soltis. Celesia rested her hand on his shoulder in reassurance, a steadying touch reminding him that he was not – quite – alone.

"They must be in their homes. No-one can know how to react to this... I don't blame them for seeking security."

Another impact sent a tremor through the city, and Castiel had to agree. His own longing to be at Source Thirteen wasn't too different, hoping to bury his fears in fighting against them, in working to keep Soltis' defences strong. Those whose daily lives had nothing to do with it – what could they do in this nightmare other than gather together, wait, and hope?

Celesia's light touch shifted into a gentle push. "Come, Engineer. Let's go to your Source."

Glancing over his shoulder at her, he nodded, and forced himself to start walking again, trying to ignore the strange, muted echoes their footsteps stirred up. This would pass. It would have to.

It wasn't, ordinarily, a long way to the Source. Even without taking any of the numerous teleporters, it was little more than a fifteen minute walk from the point they'd already reached. Yet in the echoing silence, underscored by the rumbling tremors caused by the Moon Stone impacts, it seemed a lot longer. The moment they reached the outer door of Source Thirteen and Castiel's identity registered with its sensors, however, everything changed. The thick, sturdy door slid open into the outer corridor, and even there, they could tell the air was different. It carried a sense of tension, like a permanently held breath. Castiel sped up to a run almost without realising, dashing around to the control room. Once again, the door opened for him without complaint, and several shifts worth of people looked at him at once.

"Fourth Engineer Castiel – and Sector Prime Celesia. She's here to find out what happened to the Core."

A moment of silence greeted him before the ageing First Engineer stood up, pure white streaking his already pale blond hair. "Sector Prime."

"You're the First Engineer of Source Thirteen?" she asked, and he nodded.

"Yes."

"How is the Source coping with the demands of powering the Dome of Light?"

"Well, as far as we can discern, Sector Prime. Following the blackout, we initially cut all power to non-essential functions, steadily increasing it as the Source proved capable of taking the strain. We've replaced a main feed and several other parts that were damaged by the surge, and the Source is now providing almost five thousand percent of its theoretical acceptable capacity."

"Acceptable capacity?"

"The Source is not an infinite resource, extremely refined though it is. There is a limit to the amount of energy we can extract from it. All the limits of our systems are set such that the acceptable usage is the drain which, if continued indefinitely, would result in complete exhaustion of all power in one thousand years. The average load is usually around ten percent."

"So at this rate, the Source can continue to power both this section of the Sector and its portion of the Dome of Light for another twenty years?"

"Yes," he answered. "Provided that the Dome of Light can withstand the... the Moon Stones."

"It will. Now, have you found out what _caused_ the blackout that we experienced shortly before the Moon Stones fell?"

The First Engineer shook his head. "No, Sector Prime. At first, we suspected an attempt at sabotage followed by an attack, but we could find no evidence of such. I would suggest it was a result of a momentarily unequal power supply during the activation of the Dome of Light, causing it to draw more heavily on our resources than we could handle, but that would merely be conjecture."

Celesia frowned slightly, drawing fine lines across her brow. "So it was a power drain from elsewhere rather than a malfunction here at the Source?"

"That's right."

"But the Dome of Light has been raised many times before, and nothing happened then. If it was caused somewhere else, could it happen again? And do we have any way of tracing it to its source before it does?"

He took a moment to consider her questions before responding, thoughts still flicking across behind his surprisingly expressive face.

"Since we don't know what caused the drain, if the cause were to happen again, then yes, at present, it could. We'd need to install additional safety features to be able to prevent something like that from blacking out the area, and we'd need to cut the power flow temporarily to do so." He shook his head. "We might be able to install safeguards on a rolling basis, switching circuits one at a time and using backup systems to maintain full throughput, but I wouldn't like to try it while the Dome of Light is still... active." A pause. "I don't know if we can trace the source of the fault or not. But we will try." He bent to a console, lightly keying in information, his voice providing authorisation and additional commands in a whisper that hung in the silent, tense air. For a moment, everyone simply watched.

"What are you waiting for, Engineers? Duty shift, monitor the Core; evening shift, trace the source of the power drain. Everyone else, try to work out what safeguards we could implement in what timeframe, and how we'd need to divert power to do so. Go!"

In an instant, the room was a bustle of activity, the silence broken. Castiel hesitated for a moment, just long enough to see the First Engineer glance at him.

"You're seconded to the Sector Prime until this is over. Give her whatever she needs. When we have a result, she'll be the first to know."

Surprised, Castiel could only nod.

"Castiel?"

He turned, finding himself looking into Celesia's eyes. "Yes?"

"Will you show me around the Source facility?"

"Of course." He walked back to the door, gesturing for her to follow him, and stepped into the corridor with her close behind. "It's pretty simple. The Source itself is housed in the central column – you can see it shining through the observation ports. Look." They were passing a window into the central chamber, and he pointed through it. Within the core chamber, a network of slim, strong columns crossed at all angles, meeting the thicker central column in the exact centre of the room. Sure enough, white light spilled across the chamber from its heart in several differently-oriented beams, pulsing slightly in time to the impacts they could still feel and dimly hear. "The support rods carry some of the power as well, but mostly they're there to support the city. Column maintenance seems like a pointless task while you're doing it, particularly since they already self-repair, but if something were to happen to them, well... this section of the continent would only be supported from the outside."

Celesia nodded. The refinement of the Moon Stones that had once been scattered throughout the continent had seen them concentrated into ever fewer locations, each one concentrating all the power once held in an area many kilometres in radius into a single point at its heart. Source Thirteen was fairly weak, as such things went, but the amount of power held within it was staggering. The city around it had to be stupendously well-designed to allow so wide an area to hang from so small a point.

"Should we go in?"

She looked at him and nodded. Passing one of the several doors into the central chamber, Castiel turned towards it, holding his hand to it for a moment to signify he wanted to enter. Recognising him, the door opened and let him in, Celesia at his side.

The windows in the outer corridor had been lightly tinted. The first impression of anyone who walked into the room was of brilliant, shining white, circuitry patterns in walls, floor, and ceiling blazing pale silver-blue. Castiel closed his eyes for a moment, and when he opened them again, he could see the subtle differences in colour delineating sections of columns, walls, and ceiling, both aesthetic and instructive.

"The main column houses high-demand links like the Dome's power supply and the local essential subgrid. The others carry less essential functions and backup circuits." He stopped, frowning. "Is that...?"

"What?"

He simply pointed, up and across. A smear of soot darkened the side of one of the angled columns, indicating something had blown out. He'd never seen damage like that within the Core itself before.

"What does that column carry?"

He frowned for a moment, continuing a little further around the circular walkway to get a better look at it. "It's one of the links to the main Soltis grid... I think. But that doesn't make sense. I'll have to check it against schematics."

"Why doesn't it make sense?" She continued before he could respond, answering her own question. "If the problem wasn't here in Source Thirteen, then the damage must be along the path of the drain, mustn't it?"

Castiel nodded. "Right. There's no reason for anything else to have suffered that badly. That can't be a grid feed..." He'd been sure it was, but it couldn't be. He wouldn't be able to call himself a Fourth Engineer much longer if he kept this up!

"Or perhaps it can," Celesia said thoughtfully. "Perhaps whatever it was _wasn't_ the Dome of Light after all."

He looked at her in surprise. "Then what else could it have been? Sabotage?"

"I don't know," she admitted. "But if that blackout we experienced came from the main grid, then the problem may be a lot worse than we thought. The Dome of Light is on a completely separate system, isn't it. Are they supposed to be able to interfere with one another?"

"No. The Dome runs from a high-capacity priority feed." Instinctively, he glanced up, eyes focusing past the ceiling to the distant sky and the Moon Stones he could still imagine all too clearly with every impact. "It overrides just about everything in an emergency."

"So when we put the Dome up, we should have cut ourselves out of the main grid, not poured power into it?"

"That's right," he said, slowly. "Nothing would have blown there." He shook his head. "I have to be wrong. I'll find the schematics – my tools are still in my locker. Let's go."

She smiled a little. "No need. Seren?"

The liqueform slipped from her hair again, floating to her raised hand in its default spherical shape.

"Link to the network, please. And accept non-conflicting commands from Fourth Engineer Castiel until further notice."

Seren chirped in what Castiel took for assent, forming itself into a floating screen. Castiel stared at it for a moment, slightly stunned.

"Uh... I need the most recent schematics for the – for Silver Source Thirteen." He quickly traced his authorisation on the screen as it prompted him, noticing the smooth, matte surface, without a single ripple. To be capable of everything he'd seen it do, Seren had to be very well-constructed and programmed indeed. Barely fractions of a second later, the schematic was there, visible before him in three dimensions. He spun it around, zoomed in, highlighted the column in question, and read:

"Structural support column I-5, housing:  
Primary power feed to Soltis main grid  
Backup maintenance circuit #QRT15  
Backup..."

"...Well," he said, uncertain. "The schematics agree with me – there's nothing on that column beyond the main grid feed and some backups."

"So the drain somehow came from the main grid?"

"Or one of the backups." He shook his head. "Neither makes any sense. The Dome has its own dedicated circuit that's completely closed off from everything else. There's no reason for the grid's demand to spike when it's activated unless something's very wrong somewhere. Besides, nothing's ever happened when the Dome's been activated before." His eyes scanned down the list. "None of these backups have any reason to cause a drain like that, either. Most of them shouldn't be drawing more than standby power anyway."

"I see." Celesia paused, thoughtful. "What would happen if another Source dropped out of the grid as we did?"

Castiel frowned. "Grid demand would spike, I guess. You think it could have been a problem with another Source?"

"I don't know," she responded, "but there must be some reason for the main grid to have demanded more power. What would it take for our local subgrid to black out?"

"A lot." He shook his head. "The subgrid demands _can_ be overridden, but they're on an essential feed in the central column. The Dome of Light and a few other functions have priority, but not much else. Ah... Seren?"

The liqueform chirped in a decidedly interrogative tone, managing to sound curious.

"Can you show me a timeframe of all failures and repairs within Silver Source Thirteen over the course of yesterday?"

This time, it gave a quick double-chirp of what he took to be assent, then paused for an instant before displaying a list on its floating screen. It clearly recalled his authorisation, matching it to his voice and appearance; he hadn't needed to input any information other than the request. Castiel's eyes scanned down it, one finger on the screen to drag the list up and down. Celesia watched, attentive, curious.

"From the look of this list," Castiel said slowly, "the grid feed was the first to go. Everything after that failed in an immediate cascade for some reason. ...Seren, co-display the power demands on the Source over the same day, with each incident marked."

Another chirp noted his request, and the list dissolved into a graph – one that at first glance looked almost flat save for an incredibly high, short-duration spike. Castiel took one look at the upper value and blinked, scarcely believing his eyes. Whatever it had been, even the current demand of powering the Dome of Light was almost insignificant compared to it! He took the screen by one edge and angled it so Celesia had a better view, pointing with his other hand.

"Look at that! That's the power the Source was being called on to output – this spike must be what did it!" He traced his finger along the line of the graph, a smoothly curving rapid buildup followed by an instantaneous drop to just above zero at the moment tagged with the failure of the link to the Soltisian power grid. "Something demanded an incredible amount of power for some reason, and by the look of that, it was on the main grid." He frowned. "Seren, switch to a logarithmic scale on the power axis and limit the time to an hour either side of the activation of the Dome of Light."

Seren complied at once, effectively magnifying the lower power values and making the peak appear smaller – if Castiel didn't look at the numbers. On that scale, it was clearer what had been happening. At first, demand was almost constant, followed by a quick increase, then that instantaneous drop as the main grid supply blew out, followed immediately by a cascade of other failures while the demand was at normal. That, he knew from experience, was understandable. The Moon Stone couldn't be drawn on then turned off merely at the touch of a button: there was always a moment or two of response time. Going from that amount of demand back to just ten percent of acceptable capacity would have resulted in what was effectively a burst of excess power, forced into systems that couldn't handle it and resulting in destructive overload of several components. He could just about see the stepping-up afterwards as the other Engineers must have begun repairing and reactivating the shut-down systems, overlaid on another sudden increase.

"Show me the main grid and Dome of Light demands as separate traces."

Two further lines appeared on the screen, the grid in red, the Dome in light blue. The grid line matched the spike perfectly, the Dome of Light at zero until shortly after it had ended. It showed miniature peaks that Castiel realised with a chill feeling were probably correlated with the impacts he could still dimly hear and feel reverberating through the city.

"So whatever that was," Celesia murmured, "it wasn't the Dome of Light."

Castiel shook his head. "No. Looking at that, it can't have been. That spike's our blackout, and the Dome wasn't even raised until shortly afterwards." He sighed. "I can't think of _anything_ that would have caused a spike like that, on any of the circuits."

"Do we have any way of telling what it was?"

"I'm afraid not. Once something's on the main grid, it's outside our purview unless it's within Source Thirteen's area – our job is taking care of the local subgrid, our area of the main grid, and the power links within this chamber. We usually just have to trust that most of the grid demands make sense. I can put in a request with the Spire Engineers, though – they should have the data available."

Celesia nodded. "Do it at once. This could be vitally important." She looked up as another crash echoed dimly through the walls and floors of Soltis. "Until this is over, anything we don't understand could mean the difference between life and death."


	4. Matters of Priority

Hi! Sorry this has taken so long to upload, RL happened to me. Hopefully you haven't all forgotten this story just yet! There may be some rather infrequent updates next month, too... like a fool, I've signed up for NaNoWriMo again!

All reviews appreciated, let me know what you think - I'm always looking to improve!

* * *

The day wore on as the Moon Stones continued to fall, impossible, incomprehensible. Castiel's data request went out to the Soltis network, and vanished into silence. Still, somehow, Celesia kept up with the flow of demands placed on her by her Sector, communicating, coordinating, and unobtrusively watching the engineers of Silver Source Thirteen as they went about their tasks, giving their all to their work. The Source needed little enough maintenance, but they could monitor it, study the damage's pattern as Castiel had begun to, and plan for the rolling installation of whatever safeguards they could. Another night began to fall, Soltis' internal illumination changing slightly in tone as a gentle reminder of the time outside. Off shift and off duty, Castiel leaned against a wall in one of the observation rooms, the past two days trailing each other around in his head. The power drain that had blacked out the local subgrid already seemed terrifyingly far away, normality left behind. He'd come to report to Celesia, but found her sitting against the wall, her head bent forwards slightly, and he wondered if the stress and exhaustion was taking its toll on her as he could feel it was on him.

"Sector Prime?"

"Mmph?" She raised her head, blinking. "Oh... Engineer Castiel. Have the Spire Engineers responded yet?"

He shook his head. "No... I guess there must be any number of requests going through, with... this." He waved his hand vaguely towards the ceiling, unable to avoid picturing the endless rain of Moon Stones, the terrible, wounded sky. "They must be as busy as we are. If everyone's requesting information at high priority, and they have the grid to worry about as well as the Dome of Light and the Spire itself... they probably haven't even had time to look at it."

"That's not good enough." She paused. "I understand that there must be an incredible demand on them, but if we suffer a further incident like that, and it interferes with our supply to the Dome of Light..."

Castiel swallowed and nodded. The consequences would be devastating. He'd seen some footage of the continent outside the city itself, the land wracked and torn, pitted beyond recognition. None of the rolling green that had once characterised the landscape had survived, and all that remained was a blasted, cratered, smoke-stained expanse. Beneath the Dome of Light, Soltis was an island of purity in an ocean of destruction, protected by a painfully thin immaterial shell. If the Dome so much as flickered, Soltis would go the same way.

"I'll ask the First Engineer to give my request his priority override authorisation. That should get it to the top of the pile." Nobody but the First Engineers could make such high-priority requests, and they very rarely did. Even in a time of crisis, they wouldn't use it unless they needed critical information. That would be bound to get some response, at the very least an acknowledgement that the request had been received and was being dealt with.

"Good," Celesia said, tiredly. "Let me know what the response is as soon as you have one. In fact..." She raised a slender finger, and Castiel noticed it wavering slightly. "You can have my authorisation as well, if you think it will help. I know the First Engineer's override should have a higher priority than mine in matters of engineering, but maybe it'll help demonstrate just how important this is."

"I'll put it through after his." He unclipped his workpad from his belt. None of them had racked their tools since checking them out, nor left the Source, regardless of whether or not they were supposed to be on duty. Flicking through options with a quick gesture, he sent a call through to First Engineer Vandin, finding it answered almost at once.

"What's the problem?" Even the indefatigable First Engineer's eyes were shadowed with held-back strain.

"No problem," Castiel responded. Nothing more had happened to the Source; it was the stress of waiting in the nightmare around them that was wearing on them all. "My request to the Spire Engineers for the main grid data hasn't been answered. I wanted to ask if you could give it your override authorisation."

"You'll have it," Vandin affirmed. "We can't risk something like that happening again. Is the Sector Prime with you?"

"Yes." Castiel turned and angled the workpad so its inbuilt camera could see Celesia as she stood.

"Sector Prime, we've made our plans for the rolling installation of safeguards. They include a main grid cutoff, and I'll need your approval for that. We've prioritised it over everything else, including non-essential repairs: the backup systems are functioning well. Once the safeguards are installed and related repairs made, power will be switched back to the main circuits and similar safeguards installed on the backups."

Celesia nodded, slowly. "Very well. I'll come and review the plans with you at once." With a wave of her hand, she signalled Castiel to cut the connection, and he complied. She kept her stride even as she walked, her head high, but he thought he could still see her weariness even from behind, though she kept it relatively well hidden. It was something indefinable, underlying her proud stance, in the set of her shoulders and the fall of her feet. Castiel knew he had to look a lot worse, and found himself trying to straighten a little more, push back the fear and exhaustion just that little bit further.

The door to the main control room opened as they approached it, recognising their authorisation without complaint. There were fewer people there than before, but the atmosphere was no less charged, though the strain of it all showed markedly in everyone's eyes.

"Ah, Sector Prime," the First Engineer greeted her tiredly. "I've brought up the plans for the installation of safeguards here, if you'd go through them with me." He gestured towards his display, which was showing a complex list on the left-hand side and a highlighted schematic of the Source on the right. Castiel followed Celesia as she stepped up to take a look.

"So this is the grid cutoff you were talking about." She tapped the list entry on the screen, which opened it up to reveal additional information, as well as spinning and zooming the schematic to show the relevant locations. "You've designed it as automatic with a manual override?"

Vandin nodded. "That power drain couldn't have been countered by any of us. By the time we'd reacted, the main feed would already have blown. The automatic system will limit our power output if the main grid demands exceed the safety level we've set here, a little below the failure threshold, and ignore all requests to increase output unless they're prefixed with a new authorisation that we'll build into the system."

"Wouldn't that just cause another failure?"

He shook his head. "It would at the moment, but we're working on new ways of routing the power, as well as installing higher-capacity links to take the strain. If we're needed to output that kind of power through the main grid again, I want us to be up to the task."

Celesia smiled. Even in this crisis, the First Engineer thought ahead to the possible demands of the future. "Very good. And the manual override?"

"We still haven't ruled out the possibility of sabotage, or even just data errors, elsewhere in Soltis. It's never happened before, but since I can't yet be confident that it won't again, I wanted to retain the option to build in a manual disconnect as a last resort, at least temporarily. At this state of alert, it's possible we would be able to react in time to use it."

"Could it be used against us by our hypothetical saboteur?"

He shrugged. "Of course, if the saboteur was one of our engineers, which I highly doubt. But the most they'd be able to do with it would be to cut us out of the main grid temporarily, and it would be easily reversible. All Sources need to disconnect from the grid occasionally in order to perform certain maintenance tasks, so unless we were all compromised, there would be others to take up the slack. Remember, too, the Dome of Light has a priority feed that's completely separate from the main grid. We've checked and rechecked, and there should be no interference between them at all. They don't even share a common data connection – if we lost the entire Soltis computer network, the Dome of Light could still be raised at a moment's notice. Not a lot else would be functional, but the Dome would. The only threat to it is the backlash from another surge."

Celesia nodded thoughtfully, quietly impressed. Both the information on the screen and that which the First Engineer was telling her made a convincing case. "You have my authorisation for this modification, then. Seren, please record my acceptance of First Engineer Vandin's submission of a main grid cutoff for Source Thirteen, as of this moment."

Seren chirped, and a complex glyph appeared at the top of the screen beside the corresponding heading, marking it with Celesia's authorisation. Bound into the owner's very life-force and further imprinted with absolute loyalty, a liqueform was all but impossible to suborn in any way, particularly one as complex as Seren. Only Celesia would ever be able to give that command and be obeyed, or retrieve the authorisation codes she had stored within it.

"Is there anything else you need my authorisation for?" she asked.

"Not as such, Sector Prime. If you'd like to look at some of our other measures, you're welcome to, of course, but I'll have my engineers get started on those cutoffs while you do it."

Celesia nodded. "Very well. Thank you."

As the First Engineer called up a separate window on his display, Celesia backed off, standing unobtrusively against the wall. Still seconded to her as far as he knew, Castiel followed.

"Seren, show me the complete list of modifications submitted for Source Thirteen."

Forming itself into a screen again, the liqueform obliged, producing the same list that Vandin had been showing her just moments before. Celesia ran through it quickly, looking closer at a couple of the subheadings, occasionally nodding to herself. Castiel doubted she knew much about engineering, but it was understandable for her to want to understand what was happening in the very location where she had set up her temporary headquarters during the crisis. After a little, she reached the bottom, and paused, thoughtful.

"Show me Fourth Engineer Castiel's recent high-priority request to the Spire Engineers for data on the main Soltis power grid."

Castiel reflexively leaned closer as his query appeared on the screen. Smiling slightly, Celesia took hold of one corner and angled it so that he could read it a little easier. His own high priority authorisation glyph, the visible representation of the codes he'd used to authenticate the request, was marked in the top right, as was the First Engineer's override, its timestamp suggesting he'd added it immediately after they'd spoken. The request was short and to the point, stating what data he wanted and why, briefly covering the sequence of events that had led to the blackout at Silver Source Thirteen. There was no signifier of any response, not even a simple note that the matter was under investigation.

"Now, Seren, add my priority override as Sector Prime."

The liqueform chirped again, and Celesia's priority override glyph appeared in the top right below the First Engineer's.

"There." She leant back slightly, resting against the wall. "Now... we wait."

Castiel nodded. There was no more they could do to speed his request now.

Celesia stood quietly for a little longer before pushing herself off the wall with a sigh, straightening once more. "I'm going to go back to the observation room. It seemed as though I was out of the way there, and I'll still be able to monitor what's happening. Unless your engineers would rather I left?"

Castiel shook his head sharply, almost surprising himself, even as Vandin spoke.

"No, you'd be welcome to remain. The Source itself may not be affected... but the people draw strength from you." He smiled, strained though the expression was. "Besides, Source Thirteen will hardly suffer from hosting its Sector Prime in a crisis."

Celesia smiled faintly back, and Castiel felt a certain degree of relief. While it was true that she could oversee her Sector as well from anywhere in Soltis, he found that, just as Vandin said, he didn't want her to leave. The First Engineer was right: they were all drawing strength from her. It made him wonder where she found her own.

"Thank you." She began to walk towards the door, and paused, looking over her shoulder. "Engineer Castiel, would you come with me?"

"Of course," Castiel said at once. He followed her back out of the control room, stepping forward to lead the way as she glanced around for a moment outside the door. Several engineers hurried past them, evening shift faces mostly less familiar to Castiel, and he realised the First Engineer must have had them awaiting Celesia's approval.

"Sector Prime!"

Celesia nodded in acknowledgement, and the engineer who'd spoken smiled before going on her way, seeming heartened despite the dull booming still echoing through the city. Castiel realised with a shock that he'd almost stopped noticing it himself, the sound and vibration blending into the background as the nightmare became his world. Thinking about it again, he looked up as they walked, at the white ceiling they passed beneath, its circuitry silver-blue. Somewhere above his head was that new and terrible sky, smoky black split only by the burning trails of yet more Moon Stones falling. He wasn't sure whether it frightened him more to think of it again... or that it had almost faded into the backdrop of his life.

"It feels like forever, doesn't it?" Celesia said softly. "It's only been two days, and yet it seems so much longer."

"I'd almost stopped hearing it. I can hardly believe I – I almost stopped hearing it." He turned right automatically, walking into the observation room. "It just doesn't stop."

"It can't last forever," she said, following him in and crossing to look at the Source through the tinted window, its light still pulsing slightly in time to the impacts. "There will be an end... there must be."

Castiel wanted to say that he hoped she was right, but something held him back. Her voice was wearier again, a little of her demeanour relaxing from the unbreakable Sector Prime she showed her people. He searched his mind for something else to say, found it in a chance memory. "We've got enough power to hold out for twenty years, and that's just Source Thirteen. It won't last that long."

Celesia looked over her shoulder and gave him a tired smile. "You're right."

He joined her at the window as she spoke, noticing one of her hands resting unconsciously against it. Silver Source Thirteen and its brethren were all that protected them from the horror that was the outside world. Though it blazed with light and a power Castiel could have sensed over a hundred metres away, it suddenly seemed all too frail a shield. He bowed his head. They had to be strong, not just himself and Celesia, but all the Silvites everywhere, both in Soltis and in other cities, if their shields had withstood the bombardment. If they didn't, there would be not even an echo left of their existence.

For a little while, they watched the Source, and the engineers moving around inside the chamber. One at a time, they were methodically opening up the angled support columns, making careful changes, replacing parts and laying new circuits. The modifications were going ahead.

Castiel's thoughts were interrupted by a soft chime from his datapad, one mirrored just instants later by a chirp from Seren. Celesia looked at the liqueform as it slipped from her hair once again and became a floating screen.

"The Spire Engineers?"

"I hope so." Castiel was already pulling his datapad from his belt, and had it active just moments later. He had one priority update, besides the list of modifications he knew the First Engineer had pushed out across the Source Thirteen subnet. "It is!" His query appeared on the screen in front of him, its priority glyphs bright in the top right, and a short response added at the base.

_Request received and acknowledged. Main grid power flux under investigation as a matter of priority. Direct contact: Third Spire Engineer Irides._

The message had a personal communications key attached, represented by another glyph. Castiel blinked in surprise as he re-read the last line. One of the Spire Engineers had given him direct contact permission – it wasn't unheard of, but it was certainly uncommon! They'd been right that it had been something important after all.

"Look!" he told Celesia, showing her the datapad even as he realised Seren was probably displaying the exact same thing. "They even gave me a direct contact. I knew something like that on the main grid had to be important!"

"Spire Third, too." She smiled. "That's good. I feel better knowing that." Being a Spire Engineer at all was a position of rank, one that Castiel couldn't yet do more than dream of. A Spire Fourth was more or less equivalent to a Source First, and Spire ranks only went down to Fifth. If this Irides gave an order, all of Source Thirteen would be expected to get it done.

"So do I." Relieved, he clipped his datapad back to his belt. Knowing that someone else, someone likely more capable than any of them, was looking into Source Thirteen's problem made him feel more hopeful that it would soon be solved. Whatever the flaw or failure on the main grid might have been, it would be addressed before it could strike again – and potentially threaten the safety of Soltis itself.

Celesia turned back to the window, and Castiel found himself doing the same, watching the pulsing light more than the engineers who still made their way around inside. It was almost hypnotic, in its way, frightening and reassuring at once. As long as that radiance shone, Soltis was safe, but it seemed such a slender, immaterial thread to protect them all. He'd never thought of the Source as weak, never held doubts about its capacity until the Moon Stones had begun to fall. The images of the outside world, necessarily hazy and blue through smoke and the Dome of Light, that were showing on all the newsstreams had driven home to the whole of Soltis what true destruction really was. Entire islands had been ravaged by the Gigas, reported on with quiet Silvite superiority, observed from afar, reconnoitred by autonomous drones. Cities in other lands had been levelled before, craters blasted into soil and bedrock. Even Silvite islands had suffered: though Soltis itself had rarely come under attack for long, fringe islands seemed to be considered suitable for futile demonstrations of power by the other civilisations. All life had been wiped from more than one of those small and long since evacuated islands, and he'd seen the damage then, but even that was nothing, nothing at all like this.

"Sector Prime?" he asked quietly.

"Yes?"

"Do we... do we have any contact with the other cities?"

Reluctantly but unsurprisingly, Celesia shook her head. "No. There's been no word for hours now. All the ground links have been severed, and there's a lot of interference due to the Moon Stones and the activity of the Dome. We can't lower it even for the moments it would take to send a scout drone out, even assuming one would survive long enough to make any kind of contact." She sighed. "I hope that they're still out there, but their shields aren't as strong as the Dome of Light... we have to assume that we're on our own now. From the reports I had earlier, there haven't been any detectable transmissions from anywhere since noon."

_Anywhere_. Castiel's eyes widened as the implications occurred to him. "The other Moons...?"

"Nothing." She paused, considering, perhaps deciding what to tell him. Castiel knew she had to have access to a lot more information than he and his fellow engineers did. Celesia's role as Sector Prime hinged on collating information from all areas of Silvite life, and directing the appropriate responses to it. Just as Castiel had to trust that the demands of the main grid made sense when his Source was asked to output power, so too did he have to trust the Sector Prime, and above her the Elders themselves, about matters that had nothing to do with his own limited sphere of influence. "We've lost all of our external monitoring systems now, but the signals we were getting early on all indicated panic. We can't be sure, but we suspect that all four Moons around us are undergoing the same... outburst. If they are, we can only assume that the Purple Moon is as well." She bowed her head. "We could be all that's left already."

A chill of horror froze its way down Castiel's spine. Nowhere was safe, the entire world brought to ruin. He wouldn't have thought of asking the other civilisations for help – they were at war, and in any case, what help could they possibly give to the Silvites? – but he had assumed they were out there, another constant of the world, watching the bombardment from relative safety and doubtless thanking fate that they had been spared the ruin even now being visited on his people. Now, forever behind the Silvites in development as they were, they were likely all dead. Even the worst horrors of the Gigas War were nothing compared to this.

"We can't be..."

But even as he said it, he knew it was all too likely that they were. That if they survived at all, then when the terrible destruction came to an end and they looked out once more on the devastated world, the only people left in it would be the Silvites of Soltis.


	5. The Third Day

Hi all! Well, real life happened again... trying to write original work and fanfic all around a PhD while family drama goes on in the background isn't conducive to getting things done! But, like the Silvites of Soltis, I _will_ fight on! Updates are probably going to stay unpredictable for the foreseeable future, so my advice is to put on a story alert if you want to be sure to catch what happens next. Hope you enjoy, and don't forget to let me know what you think!

* * *

The night passed much as the previous one had, albeit indoors in the familiarity of Source Thirteen. Very few of the engineers were willing to go back to their homes in the crisis, the few who did almost entirely those, such as Meredin, with young children. Like most people his own age, Castiel lived alone: there was nothing to go back for, no-one to reassure or seek reassurance from. In the comfortably controlled environment of Soltis, the worst he could expect from a night spent sleeping at the Source was a little stiffness from the hard floor. Though there were a few foldaway beds in a back room, designed long ago to cater for emergency situations that might see the need for a constantly cycling shift of engineers, they were by no means enough to serve the number of people who were actually there. The Sector Prime had been given one, but most of the engineers were simply sleeping wherever they could find space, when they could sleep at all.

It was a chime from his slate that woke Castiel early that morning, calling insistently for his attention and making him sit up. For a single, brief, glorious instant, he thought that the rain of Moon Stones might have stopped... only to be called harshly back to reality by yet another rumble reverberating through the city. He pulled the slate from his belt with one hand, rubbing his eyes with the other. It wasn't a duty chime, nor the morning alarm that he'd suspended in this terrible disaster. No, someone was calling him, the identification automatically appearing as Spire Engineer Irides. He ran a hand quickly over his unbrushed hair, suddenly acutely aware of how dishevelled three days without a wash had left him, and answered.

"Engineer Castiel." Irides didn't actually look much better than he himself, narrow features drawn, eyes shadowed by strain. "About your request for the main grid data."

"Yes?" Castiel said after a moment, when it seemed that Irides was waiting for something. The other engineer went on.

"Some of that information is classified to the level of Spire First. I can't release it in full."

Castiel's eyebrows lifted, unguarded surprise clear on his face. Irides continued before he could think of the right question to ask. "I can give you the unlabelled grid data. The demand spike that you were concerned about was a legitimate request, and I have received assurances that it won't happen again during this crisis." Pale green eyes met Castiel's through camera and screen, and he saw his own fears reflected there. "I tried to find out some additional information, but I don't have that level of access, and Silver Source Thirteen's 'supply failures' were apparently insufficient for a discretionary clearance." Irides was frustrated, he could hear it. "I sent the unlabelled data alongside this call." A moment's hesitation. "Sector Prime Celesia gave you her priority authorisation. Perhaps she'd have more luck requesting the information from the Elders than I have from my First Engineer."

Castiel nodded. It was likely – in all the parallel chains of command, Celesia was second only to the Elders who governed the whole of Silvite civilisation. "I'll pass it on. And... thanks."

Irides smiled, harried and faint, but there. "I want to know what all this is about too, Engineer Castiel. I don't like not knowing things – doubly so in a time like this. I can't work with insufficient information. I don't expect you to be able to either. If you find anything... I may not be cleared to know it, but at least let me know when your Sector Prime finds out what happened. Keep me informed."

"I'll do my best," Castiel replied. The other engineer nodded.

"Take care, Engineer Castiel." With that, the call ended, and Castiel's dataslate showed only the compressed data packet that Irides had sent alongside his message, containing the limited main grid records for the period of interest. If nothing else, Castiel thought, he could at least get started analysing them. He doubted he'd find much, not without the all-important labelling data, but perhaps something would stand out. Standing and brushing himself off, he left the room, stepping around the handful of other engineers who were sharing the same space, and headed for the observation room Celesia had semi-commandeered the day before. As he'd expected, there was nobody there. There were, of course, engineers working in the main chamber, though: he could see them through the window, checking relays, testing components on inactive columns, monitoring the central column and its feed to the Dome of Light. It had never before faced a sustained assault of such magnitude.

A long, drawn out shudder rolled through the city, and Castiel startled, alarmed, his dataslate and its contents forgotten as below him, many of the duty engineers did the same. As it continued, he was all but frozen, waiting for a couple of minutes that felt like hours until the end finally came with a last, violent jerk. What had that been?! He snatched up the slate again and spun its contents into the background, feverishly searching through reports, checking and double-checking until he was as certain as he could be that the Dome still held. Somewhat reassured, he started cycling through the newsstreams, searching for any information he could find.

"Engineer Castiel?"

The quiet voice from the doorway made him jump again, familiar though it was becoming, already aware who he would see as he turned around. Celesia walked in quietly, unmistakeable worry clear on her face.

"I don't know what that sound was," he told her, "but it wasn't the Dome. It's still up, and the demand on our Source hasn't changed, so I don't think any of the others can have failed."

She shook her head. "I know. It's not that..." Once again, he saw the hesitation that marked her trying to decide what to tell him, and this time interrupted it.

"What was it? What happened?"

Celesia looked down. "The Arkena Peninsula." Castiel knew the place at once, a spit of land on the continental edge, near to Soltis' perfectly geometrical borders and once, a world away, a favourite destination for overworld travellers, nearby as it was. "It... the Moon Stone impacts must have been too much. It's sheared off completely."

For an instant, he could barely breathe. He'd never been to the place himself, but it was as familiar as any Sector of Soltis. Just like that... it was gone? Not even blasted to rubble, new life to return one day, but utterly gone? All at once, the Dome of Light felt a thousand times more fragile, every artifice of Silvite power all but futile in the face of this utter destruction, raining down from the Moon that had once protected and served them as their civilisation grew. Was it now to be the instrument of their death?

"I shouldn't have told you," she said quietly, and he shook his head before thinking about it.

"No... I needed to know."

He wasn't at all sure that was actually true.

For a short while, there was only silence. Castiel broke it first, in the end.

"I got a response from Third Spire Engineer Irides." Celesia leant forward reflexively as he gestured with his dataslate. "I have some of the main grid data... but none of the labels indicating what was for which purpose. Whatever was happening to cause that power drain, it was too highly classified to warrant discretionary clearance even to a Spire Third."

"So it was intentional, not an accident or sabotage?"

He nodded. "That much I could be told, but that's all I know. Maybe you'd have a better chance of getting that information – you could ask the Elders to grant you discretionary clearance. I was given an assurance that it wouldn't happen again, not while the- the Moon Stones are still falling."

"Hmm." She frowned. "Maybe they were testing our response capability. I wasn't informed, though." A brief pause. "I suppose that does at least make it less important that we learn precisely what it was. As long as it was under our control, we can guarantee there won't be a second time."

"It seemed a bit much for a response test," Castiel said. "I mean, you saw those readings... that kind of power drain is completely unprecedented. The systems weren't built to handle it, certainly not in this Source. It's just... strange."

Celesia was quiet for a little, thinking about it. Castiel watched her, little else he could do. If he was honest, though, he had to admit that his motive could only be curiosity in the end. Horrifically ill-timed though the power drain had been, it had to be a coincidence. There was nothing, nothing under any of the Six Moons, that could have caused this utter calamity. Whatever was happening, it was outside human control.

"Well," she said eventually, "I'll submit a request and see what I get. I may never be cleared to tell you, though."

Despite himself, he smiled at her. "As long as I know someone I trust is taking care of it, I think I'll be fine with that."

Celesia lifted her eyebrows slightly, but she didn't seem displeased. "Then I'll keep you informed." A pause, and the Sector Prime was back again, the dull thudding of the Moon Stones weaving their rumbling counterpoint to her words. "I'm commissioning a report on the structural integrity of Sector Six as part of a Soltis-wide study, after what happened to the peninsula. I didn't think about it until now, but even though the impacts don't touch us directly, the shock waves could be causing damage throughout Soltis' superstructure. I'll be asking the First Engineers of each local grid to assign teams to the task. How long do you think it would take?"

Castiel frowned, thoughtful, and pulled up the block diagram of Source Thirteen's district on his dataslate, finding the total volume covered. His particular duties tended to keep him in and around the Source itself: below Vandin himself, the engineer ranks split into Source, District, Drone, and so on. Meredin was one of the four Source Seconds – one per six-hour shift – and the other Seconds were split similarly. As a result, he never had much need to look up the volume of the district itself, and a slow breath was his reaction as he saw the numbers against his memory of the ones he _did_ know, finding himself reminded of just how big Soltis truly was, innumerable legacies built one atop another... and all, now, under threat.

"It'll take a good-sized team," he told her, "and even with the automated monitors on the structural supports, it'll be a long while if you want everything checked. I'd give it a couple of days to get the data on the primary structural columns and walls, as long as we can spare all the engineers it'll take, and after that you're looking at weeks for the main stuff – boulevard bulkheads, secondary supports, all that – and months for everything, even with full drone assignment."

Celesia nodded. "I see. Thank you. Having at least the main structural skeleton will be a great benefit to us... and I may have to warn our citizens to be alert for any signs of weakness in the rest."

It could only help, he supposed. He wasn't sure he'd have thought of it, but Soltis was full of people, and while they might not be able to actively test every piece of material they passed, it didn't take any expert knowledge to report a cracked pillar or a warped wall plate. "It'll help." Perhaps he was just too tired, because once again, he found himself speaking without thinking. "You always seem to think of everything. I don't know if I'd even have thought to check on the supports at all."

Thankfully, Celesia didn't seem to mind, her response light and said with a faint, tired smile. "I do have my office to help me, you know. That said, that was my idea... I suppose it's part of what it means to be Sector Prime. I may not know that much in detail about any individual profession, but I have to understand when to call on all of them." She walked up to the window, looking down into the Source chamber, shining with its brilliant light. "After that, I must trust you to know what you're doing." She shot him a glance, and Castiel smiled.

They stood there for a little in silence, watching the work below, the rumbling sound of the Moon Stone impacts a dull counterpoint to their determination, until Seren chirped.

"What is it?"

The liqueform slipped from her hair at once, forming a compact screen showing an incoming message. Castiel backed off as she accepted, no part of her duties now.

"Vian?"

He'd heard that name a lot over the course of the past three days. Vian was Celesia's primary secretary, handling incoming requests, filtering the unimportant, scheduling elements of her day, and carrying out the thousand and one administrative tasks required to keep the Sector Prime's office running smoothly. If Celesia needed to appear on a non-emergency broadcast, it was Vian who sorted out the televisual arrangements, negotiated the correct amount of airtime, and set everything up to put her in front of the world.

"Sector Prime," Vian said, as tired and harried as the rest of them. "I'm getting a lot of requests at all levels about that last... event, far too many to answer individually. I think our best course of action would be to send out another broadcast. I've already been in touch with my counterparts in the other Sectors – they're getting the same queries, and Prime Azith is already preparing a 'cast." She paused. "Is that the core chamber of Silver Source Thirteen behind you?"

Celesia nodded, glancing over her shoulder. She'd turned her back on the observation window to answer the call.

"It's a good backdrop... I'd suggest you use it for this situation." She sighed, slowly. "Let them know you're still there, where it matters. Just seeing you there will help morale a little."

Castiel frowned slightly as they went on talking. He hadn't thought of that. Celesia had almost every function of her office with her in the form of Seren, other than the physical presence of her staff, currently filled in for by a single overstressed Fourth Engineer. He knew it didn't matter much to her where she was, but it hadn't occurred to him that others might benefit from seeing her out of the enclosed environment of the office. Yet where _could_ be closer tied to the ongoing crisis than a Source, its radiance a reminder of the power that protected them all?

"...do it simply, then," Celesia was saying as he tuned back in to the conversation. "If we have any additional information, tell me."

"Nothing, Sector Prime," Vian told her. "I... I don't think there's much else to say."

"All right." She looked up, over the top of the liqueform's screen and directly at Castiel. "I'll be running through my statement a couple of times before I send it out. Could you seal the doors for me?"

"Of course," he answered, seeing the sense in it. She didn't need other engineers wandering through. "Call me when you're finished... I'll get to work on the data Irides gave me."

A faint smile touched Celesia's expression again. "Thank you. Oh, and would you pass on my message to the First Engineer, about checking the structural integrity?"

"You wanted the primary structure done, right? I'll tell him."

Castiel let himself out, locking the door with his generic authorisation as it closed. Anyone above his rank could unlock it, and it wasn't an engineer-specific seal, so Celesia would be fine. Focusing on his twin tasks, he headed back to the control room. Once he'd told Vandin Celesia's message, then he could study the information Irides had sent him, restricted though it was.


End file.
